1. Field of the Invention
The present invention relates to a method of ion beam generation and an apparatus based on such method.
2. Description of the Prior Art
The magnetic recording medium, such as the magnetic tape and magnetic disc, has hitherto been widely applied to recording various electrical signals, for example, from video, audio, and digital systems. In a recording system that makes use of the in-plane longitudinal magnetization of a magnetic recording layer formed on a substrate for signal recording, new magnetic materials and new coating techniques have been tested and applied in an effort to improve such medium for higher recording densities. In the meantime, as an alternative approach to improve the magnetic recording medium for higher recording densities, the vertical magnetization recording system that makes use of the magnetization in the direction of the thickness or so-called "vertical magnetization" of the magnetic layer of magnetic recording medium has been proposed, for example, in a journal "Nikkei Electronics", No. 192 as issued on Aug. 7, 1978. This recording system has such a preferable characteristic for high density recording that the demagnetizing field that works on the residual magnetization in the medium decreases as the recording wavelength gets shorter. Being a recording system that is suited to high density recording by nature, it is presently studied for practical applications.
In the above in-plane longitudinal recording system and vertical recording system, it is conceivable to use iron nitride (Fe.sub.1-x N.sub.x) for a material constituting the recording/reproducing head. As a method to form the Fe.sub.1-x N.sub.x film, it has so far been known to sputter an iron target in an atmosphere of mixed gas of argon and nitrogen (Ar+N.sub.2) or evaporate iron in an atmosphere of nitrogen gas (N.sub.2). However, these methods of known art have not yet been fully investigated on how various relevant parameters are interrelated to one another in defining the condition of depositing the magnetic layer of Fe.sub.1-x N.sub.x. It is therefore impossible to positively form a magnetic layer of favorable characteristics with good reproducibility by these methods.